1. Field of the Invention
The present disclosure relates to a buffer composition, a specimen analysis method using the same, and a specimen analysis system using the same.
2. Description of Related Art
pH buffer solutions (hereinafter, buffer solutions) are widely used in biology and chemistry for maintaining a constant pH in a solution. In general, a buffer solution is composed of an aqueous solution of a weak acid and its conjugate base, or a weak base and its conjugate acid. Depending on the acid dissociation constant (pKa) of the weak acid or the weak base, the pH range where the buffer solution exhibits its pH buffer capacity is determined. However, the pKa is known to change in a temperature-dependent manner, and as a result, a pH of the buffer solution also is subject to change in a temperature-dependent manner. The tendency and the level of the pH change vary depending on the particular weak acid or weak base in use.
Fukada recites influences of temperature with respect to pH of various buffer solutions (“PROTEINS: Structure, Function, Genetics” by Harumi Fukada et al., 1998, Vol. 33, pages 159-166). To avoid these influences on pH change due to temperature, in general, the pH is controlled at a solution temperature in use (or an assumed temperature). Further, JP H11(1999)-287786 A recites a method of intentionally utilizing a pH change in a buffer solution due to a change in temperature for analysis of an object.
A specimen analyzer or a specimen analysis system for analyzing components of specimens such as blood or urine is equipped with a temperature control function such as a temperature control unit, a thermostat, a temperature-controlling portion and the like so as to adjust the temperature of a specimen or a buffer solution used for a specimen analysis method for the purpose of improving the accuracy of analysis (see JP 2007-322367 A, JP 2010-48554 A, and JP2012-215465 A).